Self-immolative nanoparticles triggered by hydrogen peroxide and pH

The azomethine-based oligomers bearing boronate groups and imine moieties in the main chain were synthesized from a dialdehyde monomer and an aromatic (oligomer 4) diamine or an aliphatic diamine (oligomer 5). Based on the oligomers, the nanoparticles with hydrogen peroxide (H₂O₂) and pH dual-responsive properties were constructed and encapsulated nile red inside. The nanoparticles disassembled either by the trigger of H ₂O₂ or by the attack of H⁺, thus leading to the release of loaded species. Compared to oligomer 4, oligomer 5 showed a faster degradation rate in the presence of H₂O₂, especially in a weak acidic environment. No significant cytotoxicity was observed as HeLa cells incubated in the nanoparticles with the concentration up to 200 μg/mL evidenced by cytotoxicity assay in vitro. Such a system capable of dual response of H₂O₂ and H⁺ may have potential application as a carrier for drug delivery.